Right Stuff for the Super Stuff

Right Stuff for the Super Stuff

John Glenn will conduct tests with a space age super-substance
called aerogel on STS-95

October 26, 1998: The coming return of John Glenn to space
highlights the differences between how the world looked to Americans
in 1962 and how it looks to us in 1998.

In 1962, as the first American to orbit the globe, Glenn reflected
on the delicate environmental balance that protects life on the
pale blue planet from the harsh and forbidding black matte of
stars.

"Each time around, I noticed a strange phenomenon. The stars
shone steady as they neared the horizon. Then they dimmed for
a bit. But the stars brightened again before actually setting.
They appeared to be passing through a layer of haze about six
to eight degrees above the earth and two degrees thick."

The haze that Glenn described was the thin line of atmosphere:
oxygen to breathe, ozone to shield ultraviolet radiation, and
carbon dioxide and methane to trap reflected heat. The gaseous
stuff of life. But from orbit, even the Earth's atmosphere acts
only as a semi-transparent window to the starlit sky.

For Glenn's first orbital flight the mission goal was to return
safely. Now 30 years later, he will use space not just as 'the
high ground' but as a working laboratory. Glenn and the other
astronauts will be making the first run at space-manufacture
for a product called aerogel. In the words of early Mercury astronauts
30 year ago, the mission will 'push the envelope' on how aerogel
can be improved. If successful, the experiment returns not just
more aerogel, but a fundamentally different kind of material,
what might be called the first "astrogel."

For windows and skylights,
the "holy grail" - according to Chemical and Engineering
News - is a transparent aerogel. Current aerogels, as produced
on the ground, however, are not completely transparent, but instead
have a slight blue haze to them. However, space-manufactured
aerogel has an improved transparency that could make the substance
usable in place of window glass.

Aerogel is a remarkable substance. It's the lightest known solid,
so much akin to air that it's sometimes called "frozen smoke."
Its insulating properties are nothing short of remarkable, protecting
virtually anything from heat or cold. It was used by NASA to
keep the Sojourner rover warm on the surface of Mars where night
time temperatures plunge to -100 degrees. A single one-inch window
pane of aerogel is equivalent to the insulation provided by 32
windows panes of glass (R-20 to R-32 insulation factors).
Truly, aerogel would make a perfect window except for one thing:
it's not perfectly transparent. Aerogel made on Earth is permeated
with tiny, irregular pores that make aerogel hard to see through.
There is evidence that the irregularities are diminished when
the substance in manufactured in weightless conditions. Hence
the experiment on STS-95. Astronauts will actually manufacture
some aerogel in orbit and see what happens. If aerogel could
be made transparent it could revolutionize household windows.
By some estimates, aerogel costs 3 times the price of glass,
but glass manufacturing costs are only about 10% of the purchase
price for windows, so aerogel window manufacturing might still
carry a large profit margin.

The first silica aerogels were
manufactured in space in April 1996 on a Conquest rocket.

A 1 inch pane of Aerogel has
the same insulating power as 32 panes of ordinary glass.

Aerogel may also have a role to play in keeping the atmospheric
line clear, the thin air gap that Glenn described more than 35
years ago. By reducing home heating costs aerogel could reduce
global energy needs and minimize the pollutants that inevitably
come with energy production. Science Magazine (1998) listed next-generation
window technology as a critical point in the US obligations to
meet its international global warming commitments prescribed
by the late 1997 Kyoto Conference resolutions. The Kyoto Conference
set international standards for a 5-10% cut in carbon budgets.
This is considered impossible by some economists without triggering
an economic recession. Under the agreement, carbon percentage
allotments are proposed as tradable items and can be bought by
industrialized countries from less industrialized societies,
in effect a stock market trading on smog.
New technology could offer a
way out. As an example, the December 1997 issue of Today's Homeowner
magazine listed NASA aerogel research ("Super Stuff")
in its cover story entitled "Best New Products for 1998."
The article concludes: "The potential market for a clear
aerogel is enormous, considering that window heat loss accounts
for up to 30 percent of energy lost from a home. A well-designed
aerogel window could lower heating and cooling costs by a comparable
figure".
Reduced industrial waste is another long-term target of aerogel
research. Not only is aerogel of scientific interest to reduce
the energy load, but also to capture waste and polluting gases
before they reach the atmosphere. The industrial group, The Attia
Applied Science, Incorporated (TAASI), concluded in 1996: "The
market for the aerogel absorbents is potentially vast. In principle,
wherever alcohol and fossil fuels are used, aerogel absorbents
could capture waste gases before they are emitted into the atmosphere."
In 1998, the scientific quest to reduce the haze continues, both
with deeper environmental study and in some small part, a remarkable
semi-transparent window insulator called aerogel. Glenn's flight
will be the first attempt by space scientists to improve the
transparency of aerogel and thus clear the view. During the STS-95
mission astronauts will test whether aerogel made in the weightlessness
of space is more transparent than aerogel made here on Earth.
As progress continues, the use of clear insulation betters the
chances that over coming generations even the atmospheric haze
will not cloud our views of the stars.